The conventional keystroke switch used in daily life and work is an integrated structure of a single pole and a single throw. The distance from the pole to the throw is constant when the pole is off the throw. During the contacting procedure, the pole makes unidirectional movement towards the throw. In a keypad utilizing such a switch, the constant distance from the pole to the throw and the unidirectional movement of the pole towards the throw determine a unidirectional and vertical movement of an operator's finger and the complexity of multi-finger operation, so a person's contact interface with the keys is mostly by fingertip. Only the fingertip is an easier and faster way for pressing keys. For people who touch keys frequently, this will restrict the degree of freedom of the five fingers on both hands, and even the whole body. A static single pose causes the operator to become tired easily and affects the efficiency and interest of the fingers, hands, body, eyes and brain. Since the pole and the throw are integrated together and the position of the pole relative to the throw is relatively constant, the operation of hands cannot be flexible and multidirectional, thus being unfavorable for the operator's adjustment and relaxation.
The Chinese patent application, of “Annularly-Arranged Mobile Keypad” application number of CN1264982A, filed by Liao, Hua Yong on Feb. 24, 1999 has disclosed a mobile keypad with single keystroke button and multiple keys. The keypad consists of a keystroke button and a number of keys annularly arranged around the keystroke button. The keystroke button is reset by a reset spring. During operation, the keys annularly arranged around the keystroke button are pressed by operating the keystroke button with a thumb so as to input numerals or perform functional operation. Although this invention employs a single keystroke button for operation, that being arranged annularly around the keystroke button are a number of switches (rather than a number of throws within one switch), so that each pole contacts and releases from each throw with a constant distance and a fixed direction. Furthermore, a spring reset is employed for the keystroke button, which adds a new feature of constant distance and fixed direction on the basis of the existing switch. This structure is still deficient regarding flexibility of operation.
The problem with which the prior art is confronted is to make the pole within a pole-throw combination have multi-directionality similar to a single finger movement. A pole in the prior art is bound by the rule of constant distance. The constant distance between the pole and the throw dictates that the finger's movement hinges on the direction and distance of the pole relative to the throw. For an operator, it is desirable that the pole moves with the finger and if necessary, the pole contacts the throw directly. By moving from a constant distance and fixed direction between the pole and the throw (when the pole is off from the throw as in the prior art), to a variable direction and distance between a finger and the throw a combination of the pole with the finger can achieve control over a synchronization action including the whole procedure of the pole's start, contact, and release. In this way, the problem concerning the stroke of the constant distance between the pole and the throw in the prior art can be overcome.
Another problem in the prior art concerns further reduction in key's size and an improvement of the operating sensitivity. There is a conflict between further minimization of the key's size in the keypad and the operating sensitivity and accuracy. The integrated structure of a single pole and a single throw leads to the usual key-in method with multiple fingers or a single finger; this input methods prevents minimization of the key's size due to ensuring the operating accuracy, and also prevents the further minimization of the input means such as keypad.